Teaching knitting is

a lot of work - or it is if you do it as I think it should be done.
It isn't a simple matter of telling people "you do it like this".
Someone I consider to be an acquaintance rather than a friend - I barely know her - phoned me yesterday to find out what I would be teaching next year at the guild to which I belong.
My answer was "nothing".
I am sure that was not the answer she was expecting.
    "Oh, it's not worth joining then," she told me.
    "That's up to you," I responded.
I didn't tell her that I am responsible for one workshop but it will be a little different from the usual sort of thing in that I won't be teaching a specific skill. I hope I can still make it interesting and worthwhile. I have some ideas for activities that might help people learn something.
But, teaching? The person who organises the workshops will have to ask me if she wants me to be involved.So far I have not been asked but I want to know in time to design a small project, write the pattern, write up some notes and so on. All that takes time.
It isn't the sort of thing the person who phoned me would realise. 
Recently I emailed someone I do regard as a friend. She does a lot of teaching in another area of craft. I know from what others have said that she is highly regarded as a teacher. That doesn't surprise me as she is a very intelligent person and also a very practical one. She has read, researched and published in her area. I had a query and I put it to her. She answered and I have written notes using her response. But, I kept it all brief. She's busy. It's the professional way to handle something.
I don't mind being asked something, especially if someone is having a problem. We should be able to help one another. At the same time I think I should be helping someone else solve the problem. There is not much point in saying "do this" unless the person understands why they need to "do this".  If they understand what they are doing they can often do it and other things by themselves in the future. 
So if people want to learn and I am asked I will teach - and I will also learn by teaching.